healthchecks

Official healthchecks for Sznuper.

Each healthcheck is a standalone C binary compiled with Cosmopolitan Libc — a single portable executable that runs on any Linux architecture (x86_64, aarch64) with zero external dependencies. No df, no awk, no runtime needed.

Available healthchecks

Healthcheck	Description
disk_usage	Disk space usage for a given mount point
cpu_usage	CPU utilization over a sampling interval
memory_usage	Memory and swap usage
ssh_journal	Detects SSH login events from journald (pipe trigger)

Healthcheck interface

Every healthcheck follows the same contract:

• Input: environment variables (HEALTHCHECK_ARG_* for user-defined args, HEALTHCHECK_TRIGGER for trigger metadata) and optionally stdin (for pipe/watch triggers).
• Output: events on stdout using --- event delimiter, followed by key=value pairs. The type field is required in every event.

Example output from disk_usage:

--- event
type=high_usage
mount=/
usage_percent=84.3
available=8G

Each healthcheck documents its arguments, outputs, and event type logic in a header comment.

Writing your own healthchecks

A healthcheck can be any executable — Go, Rust, Python, Bash, anything. It just needs to read its config from HEALTHCHECK_ARG_* environment variables and print --- event blocks with type= and key=value fields to stdout.

For healthchecks you want to distribute, Cosmopolitan C is recommended for the same reason the official healthchecks use it: one binary, every architecture, no dependencies.

See the Sznuper spec for the full healthcheck interface documentation.

License

MIT